The use of wireless devices is becoming more widespread as the benefits of such devices continue to increase along with advances in technology for such devices. Wireless devices use antennas to connect to other devices or networks during operation. These antennas generally require a power amplifier circuit for the transmission and reception of signals. Power amplifier circuits are generally well known in the art, see for example U.S. Patent Publication No. 20130043946 assigned to Qualcomm and incorporated herein by reference. The power amplifier circuits or modules are connected to a power supply and a ground within the wireless device. However, due to the nature of the signals coupled between the power amplifier circuit and the antenna, the power amplifier circuits are subject to various drawbacks. For example, in a high-gain GaAs power amplifier die, the die suffers from instability under various stress and output impedance conditions resulting in yield-dependency issues, significant post-manufacturing debugging, and high return costs. One problem is that a strong power amplifier (PA, 2nd-stage amplifier in GaAs die) current can affect the driving amplifier (DA, 1st amplifier inside PA die) ground when the PA and DA share the same radio frequency (RF) ground. The current feedback in the RF ground forms a positive feedback current between the DA and the PA to create an uncontrolled oscillation in the drive current.
Accordingly, there is a need for systems, apparatus, and methods that overcome the deficiencies of conventional approaches including the methods, system and apparatus provided hereby that includes a structural separation of the DA and the PA grounds and cut-off of the PA-induced feedback current to ensure stability under a wide-range of operating conditions.